1. Technical Field
The present invention relates in general to a system and method for programmable high precision quantization of analog variable. More particularly, the present invention relates to a system and method for using a double sampling analog to digital converter's (ADC's) first digital value to configure an inline resistor network that, as a result, provides a modified analog signal to the ADC for generating a second digital value.
2. Description of the Related Art
Computing devices are used to interpret and/or manipulate “real-world” signals, such as visual or audio signals. Real-world signals are analog by nature due to their inherent characteristics. Computing devices, however, are designed to process digital signals. When a computing device receives an analog signal, the computing device uses signal conversion circuitry to convert the analog signal to a digital signal. In turn, the computing device then interprets and/or manipulates the digital signal.
Typical analog to digital conversion circuitry is designed using a double-sampling approach. A double-sampling circuit includes an analog to digital converter (ADC) and a feedback loop that includes a digital to analog converter (DAC). The double sampling circuit samples an analog signal a first time in order to determine the most significant bits (MSBs) of a digital output's value. The MSBs are fed back to the DAC, which converts the MSBs to an analog feedback signal, which is subtracted from the original analog signal. The double sampling circuit then samples the difference between the original analog signal and the analog feedback signal to determine the least significant bits (LSBs) of a digital output's value.
The double-sampling approach results in high precision analog to digital conversion values. A challenge found, however, is that this approach requires a high-precision, high cost, digital to analog converter in order to effectively provide an accurate analog feedback signal. A high-precision digital to analog converter may account for as much as 90% of the total cost of an analog to digital conversion circuit design.
What is needed, therefore, is a system and method for providing a high-precision analog to digital conversion circuitry without using a high precision digital to analog converter.